Roseville Police Department detectives carry soil samples removed from a shed floor of a Roseville, Mich., home. Police have been told by a source that former Teamsters boss Jimmy Hoffa may be buried beneath a driveway.

DETROIT — Like many others that came before it, the latest search for former Teamsters boss Jimmy Hoffa has come up empty.

Tests on soil samples gathered last week from a backyard in suburban Detroit showed no traces that Hoffa — or anyone else — was buried there, Roseville police announced Tuesday.

"Our department just received the soil sample report from Michigan State University, after a battery of tests; the samples submitted for examination showed no signs of human decomposition," the police statement read. "As a result of these tests the Roseville Police Department will be concluding their investigation into the possible interment of a human body upon the property."

Thus ended the latest in a long string of tips and rumors about one of America's great mysteries.

Over the years, authorities have dug up a Michigan horse farm, looked under a swimming pool and pulled up floorboards in their quest for the former union leader.

Hoffa last was seen July 30, 1975, outside a restaurant in Oakland County, more than 30 miles to the west. The day he disappeared, Hoffa was supposed to meet with a New Jersey Teamsters boss and a Detroit mafia captain.

The latest search led police, reporters and curious onlookers to Patricia Szpunar's brick ranch-style home in Roseville. Police in the mostly working- and middle-class community north of Detroit recently received a tip from a man who claimed he saw someone buried there about 35 years ago and that the body possibly belonged to Hoffa.

"The police have left and the yellow tape has come down," Szpunar told The Associated Press on Tuesday afternoon. "I'm thrilled because it's over with. No more people staring at my house, driving by, walking by, pausing to stare. I can go on with my life."

The soil samples were removed Friday after officials drilled through the floor of a shed on Szpunar's property. Roseville police Chief James Berlin had said the ground would be excavated if decomposition were found in the samples.

A tipster recently came forward and a radar test revealed a shift in the soil, both of which prompted Friday's drilling. Berlin said the house may have been owned in the 1970s by a gambler with ties to organized crime.

Hoffa was an acquaintance of mobsters and adversary to federal officials. He spent time in prison for jury tampering. He was declared legally dead in 1982.

Previous tips led police to excavate soil in 2006 at a horse farm northwest of Detroit, rip up floorboards at a Detroit home in 2004 and search beneath a backyard pool a few hours north of the city in 2003. Other theories were that his remains were ground up and tossed into a Florida swamp, entombed beneath Giants Stadium in New Jersey or obliterated in a mob-owned fat-rendering plant.

Szpunar said she's just happy to have her shed back.

"My son can put the motorcycle back in there," she said.

Police had put a new, more secure lock on the shed. They gave Szpunar the key Tuesday.

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